(1) Field of the Invention
The present invention relates to an area machining method, and more particularly, to an area machining method of removing within a specified arbitrary area in a workpiece whereby a tool path without insufficient cut portion can be generated.
(2) Description of the Related Art
Using an automatic programing apparatus, when a part profile contour is specified and an area desired to be left uncut is defined in the form of an island, a program for area machining to remove within the specified part profile contour is generated so as to leave the island. When this automatic programming apparatus generates a tool path for cutting off a specified arbitrary area in a workpiece, the tool path for machining is selected as short as possible to reduce the machining time. Typically, the length of a tool path can be decreased by increasing depth of cut. However, some portions desired to be removed can be left uncut depending on the relationship among a tool diameter, depth of cut, and the like. Such the uncut portion or insufficient cut portion occurs when the depth of cut becomes larger than tool diameter, for example, such as when cutting at an acute-angled corner.
Conventionally, occurrence of such the insufficient cut portion is prevented by covering the area to be cut by the adjacent tool paths thereof by decreasing an amount of depth of cut. Alternatively, area machining is carried out disregarding occurrence of an insufficient cut portion, then the portion left uncut as insufficient cut is manually removed later.
As mentioned above, heretofore, occurrence of the insufficient cut has been dealt with by decreasing the depth of cut or by manually removing the insufficient cut portion later. However, reduction of the depth of cut increases the length of the tool path, and the later manual cutting of the insufficient cut portion is labor intensive for post processes. Consequently, in either case, there has been a disadvantage that the machining time is increased.